This application claims priority of Taiwanese Application No. 091208832, filed on Jun. 6, 2002.
1. Field of the Invention
This invention relates to a rotary woodworking machine, more particularly to a rotary woodworking machine with a rotary upright shaft which can effectuate reciprocating upward and downward movements by means of a cam mechanism during rotation.
2. Description of the Related Art
Referring to FIG. 1, a conventional upright wood grinding machine 10 is shown to include a grinding unit 11, a linear motion actuating unit 12, and a transmitting unit 13. The grinding unit 11 includes a hollow cylinder 111, an upright shaft 112 which has an upper end extending through the cylinder 111, and a sanding drum 113 which is mounted on the upper end of the upright shaft 112. The linear motion actuating unit 12 includes a cam wheel 121 and a cam follower 122 which couples the cam wheel 121 to the cylinder 111. The transmitting unit 13 includes a motor 131 with an output shaft 132, a first belt 133 which couples the upright shaft 112 to the output shaft 132 such that a drive force of the output shaft 132 is transmitted to rotate the upright shaft 112, and a second belt 134 which couples the cam wheel 121 to the output shaft 132 such that the drive force of the output shaft 132 is transmitted to rotate the cam wheel 121, thereby effectuating reciprocating upward and downward movements of the cylinder 111 so as to permit the sanding drum 113 to grind a workpiece.
However, as the actuating force of the cam follower 122 is applied to a lateral side of the cylinder 111, the cylinder 111 will deflect during the reciprocating movements and will obstruct the linear movement of the upright shaft 112. Moreover, it is desirable to have a rotary woodworking machine that is provided with a plurality of woodworking members in addition to the sanding drum.
The object of the present invention is to provide a rotary woodworking machine which can smoothly and steadily effectuate reciprocating upward and downward movements of an upright shaft when the upright shaft is rotated.
According to this invention, the rotary woodworking machine includes a linear motion stabilizing member which has top and bottom ends opposite to each other in an upright direction to define a guideway therebetween. A plunger is slidable along the guideway between higher and lower positions, and has an upper end proximate to the top end. An upright shaft extends along an upright axis in the upright direction, and includes a lower anchoring portion which is mounted to and which is rotatable relative to the upper end about the upright axis, an intermediate portion which extends uprightly from the lower anchoring portion and which has lifted and coupled segments respectively proximate to and distal from the lower anchoring portion, and an upper mounting portion which extends uprightly from the coupled segment. A lifting force receiving member has a pushed end which is disposed proximate to the lower anchoring portion and which permits the lifted segment to be rotatable relative thereto, and a securing end which is opposite to the pushed end in the upright direction and which is rotatable relative to the pushed end so as to be rotated with the lifted segment. A motor has an output shaft for delivering a drive force. A lifting lever includes a fulcrum end pivotally mounted on a support frame about a pivot axis transverse to the upright axis, a force end opposite to the fulcrum end, and a weight portion interposed between the fulcrum end and the force end. A cam member is coupled to the output shaft and the force end such that the drive force of the output shaft is transmitted to effectuate reciprocating upward and downward movements of the force end in the upright direction. The upward movement of the force end causes the weight portion to push against the pushed end so as to lift the lifted segment as well as the plunger from the lower position to the higher position. A transmitting shaft is journalled on the support frame, and is driven by the drive force to rotate about an axis which is transverse to the upright axis and the pivot axis. The transmitting shaft includes a coupling segment to couple with the coupled segment such that the rotation of the transmitting shaft is transmitted to rotate the coupled segment when the lifted segment is moved between the lower and higher positions.